Manufacture of dyestuffs



'--r'amino-pz'pf-di#tmethylbenzthiazyl) azc benzenel v81,711) forexample-.insolutionrinethylenefglycol wmedate productsf'namelythe "dixanthato and. fthiazylazobenzene "is' dissolved in`f400jparts of '""dithiocyano" "derivatives of rpzp#di-.(-rriethyl- "alcohol"containingr 40"`partsofsodiumsulphide "fwbenzthiazylazobenzene. 4 I 4('crystalsl.l The solutiorr'is-'boiledA for "1A-hour 'r A'Ihejstarting'materia'lwhichzis a diamine p:p "anddiluted'with GOUpartSLOfWatenj 'Th'edithio- Patented Feb. 6, 1945 t' l. 2,368,658

UNI- TED e sTATEs PATENT AoFFlcE lRINUFCTURE OFDYESTUFFS A--NormanlHulton Haddockilackley, Manchester, i v

. jEngland, as signor to Imperial Chemical Indus- .tries Limited, -a. vcorporation of Great Britain No ADrawing-'meplieatimnf-Mew 1.9,r-,1942efserial- N.; 443,670 In GreatBritainMay 23;;1941 l 1 ::s c1aims. (el.V 260;'12'1) vlf-The{present'inventionrelatesfntotheimanufac- Ynei-ther" (alv by oxidising.eenitroedehydrothio-pf fture ofL dyestuffs' and-ef intermediates therefor. f 'toluidine f initrd- 6 --methyl-Z-p le faminophenyl- #Accordingtothe/invention1Itetrazotisera die vbenzthiazole; ,:see?-LGermanjiSpecification#aNo.

"with an lalkyl Xanthate or an alkali m'etal thioibenzthiazyl) azobenzeneewith e. g-.fsodiumfesulcyanate,thereby 'obtaining1the corresponding phide, v012 (b) by nitrating .fpcp'edie-methyly fdxanthato; or?dithiocyano-p:pediJ-methylbenzthiazyl)azobenzeneg,obtained byftheoxidabeflZlhiaZl/l) azobenzene. wwtion' off` vdeh-ydrothiopetoluidine,v vande-reducing Thefinventio'n also v'comprises the=stepof hythe dinitro-spcphdi-(6ve-methylbenzthiazyl)azo-i' drolysing a dixanthato-'or`dithiocyano-p:pdi t f benzenethus-obtained 1- 1 f ffl(GJmethylbenzthiazyl)azobenzene obtainedin the ByV alkyl xanthateflal'soto benreferred Ito as "vabovemannerfto the'corresponding dimercaptoe Aalkyl xanthogenate orma-llioxy;:'dithioformate)` I I-^'p':p' dii-.(Gemethylbenzthiazyl)azobenzene" fand 15 mean a salt of an alkyl derivative fof-:Xanthic .or

oxidisngthey1atter'to=the"correspondingpolydixanthogenc acid,l fora-example, the ethyl deriva- 'sulphidel y tive. The.latter. itself is often called more V,briefly y Theepre'sent pol-ydisulphides represent sulphur- ./xanthic :or xanthogenie acid"- Thus; 'In may emcontainin'g dyestuis whichS-may lie-'applied to l vploy, for instance, as alkyl-Xanthate,..potassium cellulosic material from sodiunisulphideaccord- 20' 'ethylx'anthate o'r Xanthogenate'or potassium isoing to the usual practice with sulphur dyestuffs. ',p ropylxanthate.v As ,an alkali metal'thiocyanate By this means there arefiobtained bright orange- C; there may be' used in accordance with theinven- A yellow shades possessing excellent fastness to .tio'n,'..for example`"sodium orpotassium .thiosevere washing, chemick"and` light. r cyanate dixanthatoandldithiocyao derivatives' of 25' Therfollowing examples in'vvhich theparts are pzpdi- (6 imethylbenzthiazyl)azobenzene reby Weight Villustrate but do`nt limit the inveny ferr-.ed to. above, net only constitute intermediates .1. tion.

in the, described manufacture `of sulphurecon- Example 1 tainingA dyes'tuiTs,.but may lthemselves be applied .y cellulosic material fromsodium sulphide solui" tion according' tothe ,usual practice with sulphur "'jdyes'tuisZ Bythis procedure the dxanthato and e l. y i a e y .acld at 20 G...Asolut1onfof 4x8 artsofsodlum 4 dltloya-n9der1iat1ves become hydrolysedfm the nitrite-afin 5o partsof eeneentrate) suiphuric acid sodiumiulphide solution to; theicorrespnding dimercapto vderivatives'l...fIlielatter subsequently 51S addedwand'the'mlxture Stlrred at 20 :CF for Y .t e :Me hour.:-."1heftresulting:solutionisfnowlpoured ployedwith sulphuedyestuiisihereare produced "10i 9ms "Sodlgmfthtccyanate ltssolved nthe i on. the fibre the same' sulphur. dyestuis, to the mimmun.; qvfanmy. of Water arg addd and Phe 1; e produenonfin substance of which the abovemen- 40 lm @ure I s tlmd end heat'd 11p@ $9 Cdurlne tined proeesseserelate'L In'thSMWay also, dyeings l, /fhur 'The temperature 15"'m1nt31md at are obtained hayingethe.. properties already de- Sol-9 0 'Ci fOrafurthr/lhoume yellow pmd` scribed l' uctm suspension"l sethen/jltered off'and Washed :Acco1dingly,.this inventionisleto be,l regarded as 'fleezflfqmacidfwnn dry; thedithiocyano'pfp" Lkrelagting' .not/only tb the, manufacture bythe ,'45 d1*(6'methylbenzthlazynazobenzen? 5"0btamed aforesaid processes of'vgulplqmcOntamingy dye l 'forms a yellow powder which is insolule in'water "stuffs in substancegbutalso to Itheir production but dissolvesnsulphuc acidwith a red colour i on'. the br'e, that vis on theeellulosic material fItmay be 'used todye cotton in asimilar manner """drectly, .by employing in. the Lteehnique usual in ""tffth DOlYdSUlPhde d'scrbedbelowa -'---.dye1ng"with leumimri.dyesmffe the above interso `The above dimm-cyanea@=b'di 6methy1benf .Y 16 parteefdiaminQ-'p:p'edie emethyibenzthiazyl) azobenzenee: (made as :described :below': are dissolved yiri-`230 parts fofzconcentrated 4sulphurie vdi (Jfmethylberzthiazyl)"azobenzene, is made 55 Lcyano''compound becomes'therebyihydrolysed to precipitate is filtered oi and dried in air.l Itr forms an orange-yellow powder which is insoluble in water but dissolves in aqueous sodium sulphide, preferably containing a little alcohol orl glycerol, to yield a yellowish brown solution. Cotton is dyed by this solution in shades which, after exposure to the air, are bright orange yellow and possess excellent fastness to severe .washing, chemick and light.

The diamino-p z p'di (G-methylbenzthiazyl) azobenzene employed above, is made as follows. 20 parts of nitrodehydro-p-toluidine are dissolved in 700 parts of boiling ethylene glycol monoethyl ether. The solution is cooled to 40 C. and 100 parts of sodium hypochlorite solution (13% available chlorine) are slowly added with good agitation at i045 C. The yellowish brown precipiveniently seen by spotting on lter paper and examining the runout.) The brown precipitate is then filtered oii and washed with water.

Both the dixanthato compound and the polydisulphide derived from it dye cotton in yellowish orange shades from boiling aqueous sodium sulphide solutions. The shades so-obtained possess Very good fastness properties particularly in re- 'spect of severe washing and chemick.

Example 3 p 3.3 parts: of diamino-p:p'di(-methylbenz thiazyl) azobenzene (made as described in Example azobenzene is ltered off, washed with alcohol andl dried. The said dinitro compound is then stirred up with 600 parts of water containing 120 parts of sodium sulphide (crystals) and boiled for 2 hours. The product in suspension is filtered off, washed with water and then with alcohol and dried to a brown powder consisting of diaminop: pdi (G-methylbenzthiazyl) azobenzene. This compound is insoluble in water and mineral acids but dissolves in concentrated sulphuric acid to a red solution. Example 2 y3.3 parts of diamino-p:p'di(6-methylbenzthiazyDazobenZene (made as described in Example 1) (in the form of a 6.64% aqueous paste) and 110 parts of 10% aqueous sodium nitrite are cooled to 5 C. and added slowly with stirring toV 50 parts of 36% hydrochloric acid at 0 C. The temperature is maintained at 0 C. during the addition. The mixture is stirred at 0 C. for 1A hour and poured into an equal volume of a mixture of ice and water. The diazoniumcompound in suspension is now added slowly with goodstirring to a solution of parts of potassium ethyl Xanthate and parts of sodium carbonate in 200 parts of water at 60 C. During the addition, further amounts of sodium carbonate 'are added as needed in order to keep the solutionA alkaline to Brilliant Yellow paper. 'I'he suspension is stirred at room temperature for 1 hour and then at 80 C. for 1A; hour. The precipitate is ltered oi, washed with water and acetone and dried at 80 C. It is a known powder soluble in dilute sodium sulphide solution.

The above product (dixanthato p p' (6- methylbenzthiazyl)azobenzene) is hydrolysed by boiling with 50 parts of alcohol and 5 parts of sodium sulphide (crystals) for 1A hour. The resulting brown solution of dimercapto-p:pdi(6 methylbenzthiazyl)azobenzene is diluted with 200 partsof Water and filtered from a trace of insoluble material. The solution is then boiled and the aforesaid dimercapto compound oxidised,

1) are diazotised withll parts of 10% aqueous sodium nitrite as described in Example 2. The suspension of the diazonium compound so-obtained isadded slowly with stirring to a solution of 10parts` of potassium isopropyl xanthate and 20 parts of sodium carbonate in 200 parts of water at 60 C. Sodium carbonate is added as needed tojkeep vthe solutionalkaline to Brilliant Yellow paper. The'suspension is stirred at room temperature for 1 hour and then at 80' C. for f4 hour. The precipitate (di-isopropylxanthatop p' -di- (G-methylbenzthiazyl) azobenzene is filtered oi, washed with water and acetone and dried at 80 C. It is a brown powder soluble in boiling dilute sodium sulphide solution.

The above diisopropylxanthato compound is boiled with r partsgof alcohol and 5 parts of sodium sulphide (crystals) for 1/4 hour. The resulting brown solution of the corresponding dimercapto compound is diluted with 200 parts of water, and oxidised with sodium m-nitrobenzene sulphonate and the polydisulphide isolated in the manner described in Example 2.

Both the diisopropylxanthato compound andv the polydisulphide dye cotton in yellow shades from sodium sulphide solutions, of very good.l

fastness properties.

Example 4 7 thiazyDazobenz'ene (made as described below) in the form of an 8.3% aqueous paste are diazotised with 10% aqueous sodium nitrite as described in Example 1 and the mixture then diluted with an equal volume of a mixture of ice and water. 10 parts of sodium thiocyanate disf methylbenzthiazyl)azobenzene is ltered off and l washed with water until free from acid. It dyes cotton in yellow shades from aqueous sodium sulphide solution, thev shades having excellent fastness to washing and chemick.

The azobenzene employed above is made as follows: 9.7

' potassium nitrate added slowly in small quantitles, the temperature being maintained at 25- 30Q C. yAfter stirring for 2 hours the temperature is raised to -65 C. and maintained for 2 hours. The solution is then poured on to iceand the precipitated dinitro compound filtered ol and washed with water. The so-obtained dinitrop :pdi (B-methylbenzthiazyl) azobenzene is reduced to the corresponding diamino compound by boiling with 300 parts of water and 60 parts of sodium `sulphide (crystals) for 2 hours. When cool the brown product in suspension is ltered oi, washed well with water and dried.

l Example 5 n 4.15 parts of diaminop:p'di(es-methylbenzthiazyl) azobenzene made as in Example 4 in the form of an 8.3% aqueous paste are diazotised with 11 parts of 10% aqueous sodium nitrite as described in Example 2. The' mixture is diluted with an equal volume of a mixture of ice and water and added slowly with stirring to a solution of 10 parts of potassium ethyl xanthate and 20l parts of sodium carbonate in 200'- parts of water at 60 C. Sodium carbonate is added as needed to keep the mixture alkaline to Brilliant Yellow paper. After stirring for 1 hour, the suspension is heated at 70 C. for 10 minutes, filtered and in which X is one of a group consisting of thiocyano and alkali-metal allQfl-xanthato with so-` dium sulfide in an inert liquid 'organic solvent until the corresponding di-mercapto compound is formed, removing the solvent and adding an oxidizing agent until the corresponding polydisulflde is formed.

2. A sulfur dye in accordance with claim lA wherein X is thiocyano. l I

3. A sulfur dye in accordance with claim l wherein X is alkali-metal ethyl-xanthato.

4. A sulfur dye in accordance with claim 1 wherein X is alkali-metal isopropyl-Xanthato.

5. The process of making sulfur dyes which comprises heating a compound represented by the formula in which X is one of a group consisting of thiov cyano and alkali-metal alkylfxanthato wherein' alkyl has 2 to 3 carbons, with sodium sulfide in a liquid organic solvent until the X groups are hydrolyzed to the corresponding di-mercapto derivative, and then heating l said, compound in aqueous medium with an oxidizing agent until the corresponding polydisulfide is formed. l l

6. The process in accordance with claim 5 in which the organic solvent is alcohol.

.7. The process in accordance with claim'5 in v.

which oxygen is the oxidizing agent.

8. The process in accordance with claim 5 in which m-nitrobenzene sulfonate is the oxidizing agent.

NORMAN HULTON HADDOCK. 

